A human gastric cancer cell line possesses a functional receptor for gastrin-releasing peptide.
Bombesin (BBS) exhibits diverse biological functions including those of neurotransmitter, regulator of gastrointestinal hormone release, and mitogen. Gastrin-releasing peptide (GRP, the mammalian equivalent of BBS) is found in mucosal cells of the gastric fundus and antrum. We determined whether a human gastric cancer cell line (SIIA) expresses a functional GRP-receptor (GRP-R). BBS increased intracellular calcium ([Ca2+]i), and a specific GRP-R antagonist, ([D-Phe6, Des-Met14]-BBS (6-14)-ethylamide), blocked BBS-induced increase in [Ca2+]i. SIIA cells possess GRP-R mRNA by reverse transcriptase-PCR. Furthermore, these cells possess an 80-kDa cell surface protein that specifically binds BBS with two high-binding affinities (Kd1 = 0.6 nM, Kd2 = 6.7 nM). These findings indicate that SIIA cells possess a GRP-R that is capable of physiological signal transduction, though the cellular response remains unknown.
Bold
R J
RJ
Department of Surgery, University of California, Davis-East Bay, Oakland 94602, USA.
Kim
H J
HJ
Ishizuka
J
J
Townsend
C M
CM
Thompson
J C
JC
D000230:Adenocarcinoma / Q000473:pathology*; D001839:Bombesin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003432:Cross-Linking Reagents; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics; D018004:Receptors, Bombesin / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000473:pathology*; D014407:Tumor Cells, Cultured / Q000473:pathology
D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D012333:RNA, Messenger; D018004:Receptors, Bombesin; D001839:Bombesin; D002118:Calcium